... I forgot to mention that I was also told it could be Trigeminal Neuralgia:
http://www.ohsu.edu/neurosurgery/conditions/tn-description.shtml
I was also told it was a symptom of TMJ.
Folks call it "CHIN CRAMP" or "TONGUECRAMP" or "UNDER CHIN CRAMP" or "JAW CRAMP" or even "Chinitis"
Here is a good link of a possible reason as well: (24 replies)

... So, I press four fingers on my tongue pretty firmly and I move them to the back of my tongue into my throat. Then I went as far as I could not worrying about vomitting. I was already feeling like I would from the pain. ... (24 replies)

... For a few weeks I have been experiencing extremely painful cramps in my throat whenever I sneeze.
It seems like a lot of other people experience this but none of them were able to get a diagnosis. Well, I made an appointment w/my ENT Dr. & he did some tests. When he pressed his thumbs against the base of my tongue it hurt REALLY bad & he immediately said, "you have a muscle... (2 replies)